First person has some real advantages - and disadvantages. The big advantage is immediacy. As a reader you really feel you know this character, you know how they think, how they feel, their ups and downs. The big disadvantage is immediacy. If the reader doesn't like the character or finds them irritating, annoying, ditsy, too stupid to live, whatever, then you're stuffed.
A character like Sherlock Holmes would be intolerable in the first person, always condescending to ordinary mortals for not being as brilliant as himself. No wonder the stories are written from the first person view point of Dr Watson, who is amazed at how clever Holmes is. The reader is placed somewhere between them for intelligence, brighter than Watson, but not keeping up with Holmes.
Character aside, you'd also have problems with plot with a first person Holmes - or Poirot, or Miss Marple. Think of the number of times these characters work out who the killer is, but hold the information back from their companions (and the readers) before revealing all at the incredible denouement. Often is the answer, if not every time. If we were in their heads we'd have access to that information. If the writer hides the information, they risk the wrath of the reader - which is what happened when Christie published The Murder of Roger Ackroyd and Poirot's Last Case.
The final major disadvantage of first person is that of reported action which, regular readers of my blog will know, sucks. The first person character has to be present at all the major events of the story. This can lead to awkward manoeuvring to get them there or set up the dreaded reported action scene. The other solution is to start with a statement such as:
"I wasn't there, but Freddie filled me in with such detail I could imagine every minute of it. He'd been fooling around with his old jalopy when Marigold turned up.
'Hey Freddie - take me for a ride?'
'Sure,' Freddie said, revving up the engine, eyes on Marigold's legs as she slipped into the passenger seat. etc"
Hmm. Only to be used if you absolutely have to...
Advantages of first person tomorrow, when I've had more time to think of them.
Who lives near Birmingham? On 23rd June 6.30 - 8.30 Lucy Diamond, Milly Johnson, Veronica Henry and me will be talking about writing at Birmingham Library. Come and meet us!